"The Big Bang Theory" 8 p.m. CBS — Sheldon gets a surprise when he visits his mom in Houston.

"Hell's Kitchen" 8 p.m. Fox (12th season debut) — Twenty new chefs face off against Gordon Ramsay.

"American Idol" 9 p.m. Fox (new time slot) — Another woman is likely to go home.

"Grey's Anatomy" 9 p.m. ABC — Arizona advises a patient who faces a double amputation.

"Two and a Half Men" 9:01 p.m. CBS — Lyndsey learns Alan is sleeping with Larry's sister.

"Scandal" 10 p.m. ABC — Fitz thinks he is prepared for the first presidential debate but a surprise awaits him.

"Elementary" 10:01 p.m. CBS — Holmes investigates the murder of an influential cancer researcher.